Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method for feeding back hybrid automatic repeat request acknowledgement (HARQ-ACK) information, comprising: in a time-frequency bundling window corresponding to an uplink subframe in a feedback window of a first uplink subframe for feeding back HARQ-ACK, receiving a physical downlink control channel (PDCCH) or an enhanced PDCCH (EPDCCH) scheduling downlink HARQ transmission, obtaining a downlink assignment index (DL DAI) in a DL-assignment, and determining a mapping value of each DL DAI; determining a second uplink subframe for feeding back the HARQ-ACK, and determining an uplink carrier for feeding back the HARQ-ACK; mapping HARQ-ACK bits of each HARQ feedback unit to corresponding bits of a feedback bit sequence according to the mapping value of the DL DAI; and feeding back the HARQ-ACK bits on the uplink carrier in the second uplink subframe, wherein the uplink carrier includes a first uplink carrier responsible for feeding back the HARQ-ACK of an unlicensed carrier, and a second uplink carrier responsible for feeding back the HARQ-ACK of a licensed carrier or the unlicensed carrier.
A User Equipment (UE) device uses a method to provide Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) feedback. The UE receives scheduling information (PDCCH/EPDCCH) for downlink HARQ transmissions within a specific "time-frequency bundling window" linked to an "uplink subframe" for feedback. It obtains a Downlink Assignment Index (DL DAI) and determines its mapping value. The UE then identifies a "second uplink subframe" and a specific uplink carrier for sending feedback. HARQ-ACK bits for each feedback unit are mapped to a feedback bit sequence using the DL DAI mapping value. Finally, these HARQ-ACK bits are transmitted on the chosen uplink carrier in the determined second uplink subframe. This uplink carrier can be a "first uplink carrier" for unlicensed bands or a "second uplink carrier" for licensed or unlicensed bands.
2. The method of claim 1 , wherein the first uplink subframe for feeding back the HARQ-ACK is determined according to indication information in received physical layer signaling, or the first uplink subframe for feeding back the HARQ-ACK is determined according to a reference carrier and an HARQ-ACK timing of a carrier on which PDSCH is received; wherein the feedback window of the first uplink subframe for feeding back the HARQ-ACK starts from the first uplink subframe, and a length of the feedback window is configurable; wherein the second uplink subframe is within the feedback window; and wherein the time-frequency bundling window comprises all downlink subframes whose HARQ-ACK need to be fed back in the first uplink subframe, and the HARQ-ACK of the downlink subframes are arranged according to a predefined rule.
This method for HARQ-ACK feedback builds on the previous description. The "first uplink subframe" is determined either by physical layer signaling or based on a reference carrier and the HARQ-ACK timing of the Physical Downlink Shared Channel (PDSCH) reception. A "feedback window," starting from this first uplink subframe, has a configurable length, and the "second uplink subframe" falls within this window. The "time-frequency bundling window" includes all downlink subframes requiring HARQ-ACK feedback in the first uplink subframe, with their HARQ-ACKs arranged according to a predefined rule.
3. The method of claim 1 , wherein the mapping the HARQ-ACK bits of each HARQ feedback unit to the corresponding bits of the feedback bit sequence according to the mapping value of a corresponding DL DAI comprises: determining whether there is another second uplink subframe which belongs to another feedback window and overlaps with the second uplink subframe; if there is no other second uplink subframe in other feedback window, determining a number of HARQ-ACK bits according to a number of physical downlink shared channels (PDSCHs) actually being scheduled in all downlink subframes in a time-frequency bundling window of the first uplink subframe corresponding to the second uplink subframe, and determining the sequence of the HARQ-ACK bits according to a predefined rule; and if there is another second uplink subframe in another feedback window, determining a number of first type HARQ-ACK bits according to a maximum number of PDSCHs can be scheduled in all downlink subframes of the time-frequency bundling window of a first uplink subframe corresponding to the another second uplink subframe in the another feedback window, and determining a number of a second type HARQ-ACK bits according to the number of PDSCHs actually being scheduled in all downlink subframes in the time-frequency bundling window of the first uplink subframe corresponding to the second uplink subframe of the feedback window, and determining the sequence of the two types of HARQ-ACK bits according to a predefined rule.
This method for HARQ-ACK feedback builds on the previous description, specifically detailing how HARQ-ACK bits are mapped using the DL DAI. The UE first checks if the "second uplink subframe" overlaps with another "second uplink subframe" from a different feedback window. If no overlap occurs, the number of HARQ-ACK bits is determined by the PDSCHs actually scheduled in the current time-frequency bundling window, with the bit sequence following a predefined rule. If an overlap exists, the UE determines a quantity of "first type" HARQ-ACK bits based on the *maximum possible* PDSCHs in the overlapping window, and a quantity of "second type" HARQ-ACK bits based on the *actual scheduled* PDSCHs in the current window, sequencing both types by a predefined rule.
4. The method of claim 1 , wherein the mapping the HARQ-ACK bits of each HARQ feedback unit to the corresponding bits of the feedback bit sequence according to the mapping value of the corresponding DL DAI comprises: determining whether there is another second uplink subframe which belongs to another feedback window and overlaps with the second uplink subframe; if there is no other second uplink subframe in other feedback window, determining the HARQ-ACK bits according to PDSCHs actually being scheduled in all downlink subframes in the time-frequency bundling window of the first uplink subframe corresponding to the second uplink subframe of the feedback window; and if there is another second uplink subframe in another feedback window, determining a first type HARQ-ACK bits according to the PDSCHs actually being scheduled in all downlink subframes in the time-frequency bundling window of a first uplink subframe corresponding to the another second uplink subframe in the another feedback window, and determining a second type HARQ-ACK bits according to the PDSCHs actually being scheduled in all downlink subframes of the time-frequency bundling window of the first uplink subframe corresponding to the second uplink subframe of the feedback window, and determining a sequence of the two types of HARQ-ACK bits according to a predefined rule.
This method for HARQ-ACK feedback builds on the previous description, detailing an alternative way HARQ-ACK bits are mapped using the DL DAI. The UE first checks if the "second uplink subframe" overlaps with another "second uplink subframe" from a different feedback window. If no overlap occurs, the HARQ-ACK bits are determined directly from the PDSCHs actually scheduled in the current time-frequency bundling window. If an overlap exists, a "first type" of HARQ-ACK bits is determined from the PDSCHs actually scheduled in the overlapping window, and a "second type" of HARQ-ACK bits is determined from the PDSCHs actually scheduled in the current window. A predefined rule then determines the sequence of these two types of HARQ-ACK bits.
5. The method of claim 3 , wherein the predefined rule comprises: determining the sequence of the two types of HARQ-ACK bits according to a sequence of the first uplink subframes respectively corresponding to the two types of HARQ-ACK bits, wherein the HARQ-ACK bits corresponding to the first uplink subframe which is earlier in time are placed in front, and the HARQ-ACK bits corresponding to the first uplink subframe which is latter in time are placed behind; and wherein the number of PDSCHs actually being scheduled is determined according to a total DAI and/or counter DAI, and values of the total DAI and/or counter DAI are determined cumulatively in time-frequency bundling windows corresponding to all uplink subframes in the feedback window.
This method for HARQ-ACK feedback builds on the method described in claim 3. The "predefined rule" for sequencing HARQ-ACK bits involves placing bits corresponding to an earlier "first uplink subframe" before those from a later one. Additionally, the number of "PDSCHs actually being scheduled" is determined by a "total DAI" and/or "counter DAI" whose values are cumulatively determined across all time-frequency bundling windows corresponding to uplink subframes within the feedback window.
6. The method of claim 1 , wherein the determining the uplink carrier for feeding back the HARQ-ACK comprises: determining the uplink carrier for feeding back the HARQ-ACK according to indication information in received physical layer signaling; or determining the uplink carrier for feeding back the HARQ-ACK according to a current channel busy/idle state, or determining the uplink carrier for feeding back the HARQ-ACK according to indication information in received higher layer signaling, wherein when feeding back the HARQ-ACK on the first uplink carrier and mapping the HARQ-ACK bits of each HARQ feedback unit to the corresponding bits of the feedback bit sequence according to the mapping value of the corresponding DL DAI, determining the HARQ-ACK bits according to PDSCHs actually being scheduled in all downlink subframes in the time-frequency bundling window corresponding to the first uplink carrier; or feeding back the HARQ-ACK on the second uplink carrier, and do not feeding back the HARQ-ACK on the first uplink carrier, determining a number of a first type HARQ-ACK bits according to a maximum number of PDSCHs can be scheduled in all downlink subframes in the time-frequency bundling window corresponding to one of the first uplink carrier and the second uplink carrier which one has a minimum carrier index, and determining a number of second type HARQ-ACK bits according to the PDSCHs actually being scheduled in all downlink subframes in the time-frequency bundling window corresponding to one of the first uplink carrier and the second uplink carrier which has a maximum carrier index; the first type HARQ-ACK bits are arranged in front and the second type HARQ-ACK bits are arranged behind the first type HARQ-ACK bits; and wherein the number of PDSCHs actually being scheduled is determined according to a received total DAI and/or counter DAI; or the maximum number of PDSCHs can be scheduled is determined according to a number of configured carriers.
This method for HARQ-ACK feedback builds on the previous description, detailing how the uplink carrier for HARQ-ACK feedback is determined. The uplink carrier can be chosen based on physical layer signaling, the current channel busy/idle state, or higher layer signaling. If feedback is sent on the "first uplink carrier" (unlicensed), HARQ-ACK bits are determined by the PDSCHs actually scheduled in the time-frequency bundling window corresponding to that first uplink carrier. If feedback is sent *only* on the "second uplink carrier" (licensed/unlicensed), a "first type" of HARQ-ACK bits is determined by the *maximum possible* PDSCHs in the time-frequency bundling window of the carrier with the minimum index, and a "second type" by the *actual scheduled* PDSCHs in the window of the carrier with the maximum index, with first-type bits arranged first. The number of actual scheduled PDSCHs is based on received total/counter DAI, and maximum possible PDSCHs by the number of configured carriers.
7. The method of claim 1 , wherein: DL DAI includes first-category DL DAI; wherein the mapping value of the first-category DL DAI is determined, based on a starting point of the corresponding downlink HARQ transmission within the time-frequency bundle window; wherein the second uplink subframe for feeding back the HARQ-ACK is the same subframe of the first uplink subframe for feeding back the HARQ-ACK; and wherein the time-frequency bundle window comprises time units for transmitting all the downlink HARQ transmissions of an uplink subframe, which feeds back the HARQ-ACK, the time units for transmitting all the downlink HARQ transmissions are sorted according to a set rule, starting point of a time unit within the time-frequency bundle window corresponds to starting point of the HARQ feedback unit transmitted within the time unit.
This method for HARQ-ACK feedback builds on the previous description. The DL DAI is specifically a "first-category DL DAI," and its mapping value is determined by the starting point of the corresponding downlink HARQ transmission within the "time-frequency bundle window." The "second uplink subframe" used for feedback is the *same* as the "first uplink subframe." The "time-frequency bundle window" itself consists of "time units" for all downlink HARQ transmissions for a specific uplink subframe that provides HARQ-ACK feedback. These time units are sorted by a set rule, where the starting point of a time unit corresponds to the starting point of the HARQ feedback unit transmitted within it.
8. The method according to claim 7 , wherein the time unit comprises N orthogonal frequency division multiplexing (OFDM) symbols, lengths of different time units within the same time-frequency bundle window are the same or different, N is a set positive integer; wherein when the time-frequency bundle window comprises one downlink subframe, a time unit in the time-frequency bundle window is time resource from starting point to end point in a downlink subframe, starting point and end point are respectively L1th OFDM symbol and the last OFDM symbol in the downlink subframe, each time unit is sorted according to sequence of starting point of each time unit, L1 is a set positive integer; wherein when the time-frequency bundle window comprises one downlink subframe, the mapping value of the first-category DL DAI of a downlink HARQ transmission within the time-frequency bundle window is to represent total number of HARQ feedback units, which are transmitted by an evolved Node B (eNB) from a first time unit to a time unit for the downlink HARQ transmission within the downlink subframe, and from a first carrier to a carrier for the downlink HARQ transmission of a HARQ feedback unit; or the mapping value of the first-category DL DAI of a downlink HARQ transmission within the time-frequency bundle window is to represent the total number of HARQ feedback units, which are transmitted by the eNB within a time unit for the downlink HARQ transmission from the first carrier to the carrier for the downlink HARQ transmission.
This method for HARQ-ACK feedback builds on the descriptions in claims 1 and 7. Each "time unit" consists of N Orthogonal Frequency Division Multiplexing (OFDM) symbols, with N being a positive integer, and their lengths within a window can be the same or different. If the "time-frequency bundle window" contains only one downlink subframe, a time unit spans from the L1th (a positive integer) to the last OFDM symbol of that subframe, and time units are sorted by their starting points. In this single-subframe scenario, the "first-category DL DAI" mapping value represents the total HARQ feedback units transmitted by the eNB: either cumulatively from the first time unit to the current time unit (within the downlink subframe) and from the first carrier to the current carrier; or, it represents the total HARQ feedback units transmitted by the eNB *within* the current time unit from the first carrier to the current carrier.
9. The method according to claim 7 , wherein when the time-frequency bundle window comprises multiple downlink subframes, a time unit in the time-frequency bundle window is time resource from starting point to end point in a downlink subframe of the multiple downlink subframes, the starting point and end point of the downlink subframe are respectively L2th OFDM symbol and the last OFDM symbol, each time unit is sorted according to sequence of downlink subframe transmitted within each time unit, different time units of the same downlink subframe are sorted according to sequence of starting point of the different time units, L2 is a set positive integer; wherein when the time-frequency bundle window comprises multiple downlink subframes, the mapping value of the first-category DL DAI of a downlink HARQ transmission within the time-frequency bundle window is to represent the total number of HARQ feedback units, which are transmitted by the eNB within all the downlink subframes of the time-frequency bundle window, from a first time unit to a time unit for the downlink HARQ transmission, from a first carrier to a carrier for the downlink HARQ transmission, from a first downlink subframe to a downlink subframe for the downlink HARQ transmission within the time-frequency bundle window; or wherein values of the first-category DL DAI of the same time unit in each downlink subframe of the time-frequency bundle window are continuous; or wherein value of the first-category DL DAI of a downlink HARQ transmission within the time-frequency bundle window comprise a subframe-dimension DAI value and a carrier-dimension DAI value, the subframe-dimension DAI value is determined with current method, the carrier-dimension DAI value is to represent the total number of HARQ feedback units, which are transmitted by the eNB within the downlink subframe carrying the downlink HARQ transmission from the first time unit to a time unit for the downlink HARQ transmission, from the first carrier to a carrier for the downlink HARQ transmission.
This invention relates to wireless communication systems, specifically methods for managing downlink hybrid automatic repeat request (HARQ) feedback in time-frequency bundle windows. The problem addressed is the efficient tracking and signaling of HARQ feedback units across multiple downlink subframes and carriers in a bundled transmission window. The solution involves defining a first-category downlink downlink assignment index (DL DAI) that dynamically represents the total number of HARQ feedback units transmitted by an evolved NodeB (eNB) within the time-frequency bundle window. When the window contains multiple downlink subframes, each time unit within a subframe is defined from a starting OFDM symbol (L2th symbol) to the last OFDM symbol, with time units sorted by subframe sequence and starting point. The DL DAI can either represent the cumulative count of HARQ feedback units from the first time unit to the current transmission across all subframes and carriers or ensure continuous values for the same time unit across subframes. Alternatively, the DL DAI may include a subframe-dimension DAI value (determined by the current method) and a carrier-dimension DAI value, which indicates the total HARQ feedback units transmitted within the current subframe from the first time unit and carrier to the current transmission. This approach optimizes HARQ feedback management in multi-subframe, multi-carrier environments.
10. The method according to claim 8 , wherein when configured starting point of downlink HARQ transmission of each carrier in unlicensed frequency band is aligned, the first-category DAI of downlink HARQ transmission of carriers in licensed frequency band is less than the first-category DAI of downlink HARQ transmission of carriers in the unlicensed frequency band.
This method for HARQ-ACK feedback builds on the descriptions in claims 1, 7, and 8. If the configured starting points for downlink HARQ transmission on each carrier in the unlicensed frequency band are aligned, then the first-category DAI for downlink HARQ transmission on carriers in the licensed frequency band will be numerically smaller than the first-category DAI for downlink HARQ transmission on carriers in the unlicensed frequency band.
11. The method according to claim 1 , wherein when no modulo operation is performed to first-category DAI value, sequence of starting point of each downlink HARQ transmission within the time-frequency bundle window is consistent with an ascending order of corresponding DAI value.
This method for HARQ-ACK feedback builds on the previous description. If no modulo operation is applied to the first-category DAI value, then the sequence of starting points for each downlink HARQ transmission within the time-frequency bundle window will directly correspond to an ascending order of their respective DAI values.
12. The method according to claim 7 , further comprising: after receiving the PDCCH or EPDCCH, obtaining a second-category DL DAI corresponding to the downlink HARQ transmission in the DL-Assignment, and determining a mapping value of the second-category DL DAI; and mapping the HARQ-ACK bit of each HARQ feedback unit within the time-frequency bundle window to the corresponding bit of the feedback bit sequence, based on the mapping value of the second-category DL DAI.
This method for HARQ-ACK feedback builds on the descriptions in claims 1 and 7. After receiving the PDCCH or EPDCCH, the UE performs additional steps: it obtains a "second-category DL DAI" related to the downlink HARQ transmission within the DL-Assignment, determines its mapping value, and then maps the HARQ-ACK bit of each HARQ feedback unit within the time-frequency bundle window to the feedback bit sequence based on this "second-category DL DAI" mapping value.
13. The method according to claim 12 , further comprising: when the total number of HARQ feedback units transmitted by the eNB is less than, or equal to the mapping value of second-category DL DAI of a downlink HARQ transmission before current time, feeding back, by the UE, the HARQ-ACK bit, based on the mapping value of second-category DL DAI of the downlink HARQ transmission, or when the total number of HARQ feedback units actually transmitted by the eNB is greater than the mapping value of second-category DL DAI of the downlink HARQ transmission before current time, the method further comprising: updating, by the eNB, the mapping value of the second-category DL DAI corresponding to current downlink HARQ transmission; and feeding back, by the UE, the HARQ-ACK bit, based on the updated mapping value of the second-category DL DAI; wherein when the time-frequency bundle window comprises one downlink subframe, the mapping value of second-category DL DAI of a downlink HARQ transmission within the time-frequency bundle window is to represent total number of HARQ feedback units, which are transmitted by the eNB on all the carriers from starting point of the time-frequency bundle window to a time unit for the downlink HARQ transmission, or to a time unit for transmitting the DL-Assignment; wherein when the time-frequency bundle window comprises multiple downlink subframes, the mapping value of second-category DL DAI of a downlink HARQ transmission within the time-frequency bundle window is to represent total number of HARQ feedback units, which are transmitted by the eNB on all the carriers from a first time unit to a time unit for the downlink HARQ transmission in all the downlink subframes within the time-frequency bundle window, from a first downlink subframe to a downlink subframe for the downlink HARQ transmission within the time-frequency bundle window; or the second-category DL DAI value of a downlink HARQ transmission within the time-frequency bundle window comprises a subframe-dimension second-category DAI value and a carrier-dimension second-category DAI value, wherein the subframe-dimension second-category DAI value is determined with current method, the carrier-dimension second-category DAI value is to represent the total number of HARQ feedback units, which are transmitted by the eNB on all the carriers within a downlink subframe carrying the downlink HARQ transmission from the first time unit to the time unit for the downlink HARQ transmission; wherein the mapping value of second-category DL DAI of a downlink HARQ transmission within the time-frequency bundle window is to represent the total number of HARQ feedback units, which are predicted to transmit, or actually transmitted by the eNB on all the carriers from starting point to end point of time-frequency bundle window, or from starting point to the last time unit of a subframe carrying the downlink HARQ transmission within the time-frequency bundle window; and wherein the mapping value of the second-category DL DAI of a downlink HARQ transmission within the time-frequency bundle window is to represent: the HARQ feedback units of the downlink HARQ transmission are the last Y HARQ feedback units, which are predicted to transmit by the eNB on all the carriers from the starting point of the time-frequency bundle window to a time unit for the downlink HARQ transmission, or to a time unit for transmitting the DL-Assignment, wherein Y is a set positive integer, values of Y are the same or different corresponding to different mapping values of the second-category DL DAI.
This method for HARQ-ACK feedback builds on the descriptions in claims 1, 7, and 12, adding logic for the "second-category DL DAI." If the total HARQ feedback units transmitted by the eNB are less than or equal to the "second-category DL DAI" mapping value *before* the current time, the UE feeds back the HARQ-ACK bit based on that mapping value. If the total units *exceed* the previous mapping value, the eNB updates the "second-category DL DAI" mapping value for the current transmission, and the UE uses this updated value for feedback. The mapping value for the "second-category DL DAI" can represent: for a single downlink subframe window, total HARQ feedback units from window start to current time unit (or DL-Assignment time unit) on all carriers; for multiple downlink subframes, total units across all subframes from first time unit to current time unit, and from first subframe to current subframe. Alternatively, for multiple subframes, it can include a subframe-dimension and carrier-dimension DAI. Generally, this mapping value represents *predicted or actual* total HARQ feedback units from window start to end, or to the last time unit of the subframe. Another alternative is that it indicates the current HARQ feedback units are the *last Y* predicted units (where Y is a configurable integer) from the window start to the current time unit.
14. The method according to claim 12 , wherein the mapping value of the second-category DL DAI of a downlink HARQ transmission within the time-frequency bundle window is to represent: the HARQ feedback units of the downlink HARQ transmission are the last X HARQ feedback units on all the carriers, which are from the starting point of the time-frequency bundle window to a time unit for the downlink HARQ transmission, or to a time unit for transmitting the DL-Assignment, wherein X is a set positive integer, values of X are the same or different corresponding to different mapping values of the second-category DL DAI.
This method for HARQ-ACK feedback builds on the descriptions in claims 1, 7, and 12. The mapping value of the "second-category DL DAI" for a downlink HARQ transmission within the time-frequency bundle window is defined as representing that the HARQ feedback units of the current downlink HARQ transmission are the *last X* HARQ feedback units on all carriers, counted from the starting point of the time-frequency bundle window up to the time unit for the downlink HARQ transmission (or up to the time unit for transmitting the DL-Assignment). X is a configurable positive integer, and its values can be different depending on the specific mapping values of the second-category DL DAI.
15. An apparatus for feeding back hybrid automatic repeat request acknowledgement (HARQ-ACK) information, comprising: a transceiver; and a controller connected to the transceiver, the controller is configured to: in a time-frequency bundling window corresponding to an uplink subframe in a feedback window of a first uplink subframe for feeding back HARQ-ACK, receive a physical downlink control channel (PDCCH) or an enhanced PDCCH (EPDCCH) scheduling downlink HARQ transmission, obtain a downlink assignment index (DL DAI) in a DL-assignment, and determine a mapping value of each DL DAI, determine a second uplink subframe for feeding back the HARQ-ACK, and determine an uplink carrier for feeding back the HARQ-ACK, map HARQ-ACK bits of each HARQ feedback unit to corresponding bits of a feedback bit sequence according to the mapping value of the DL DAI, and feedback the HARQ-ACK bits on the uplink carrier in the second uplink subframe, wherein the uplink carrier includes a first uplink carrier responsible for feeding back the HARQ-ACK of an unlicensed carrier, and a second uplink carrier responsible for feeding back the HARQ-ACK of a licensed carrier or the unlicensed carrier.
An apparatus (e.g., a User Equipment or UE) for providing Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) feedback comprises a transceiver and a connected controller. The controller is configured to: receive scheduling information (PDCCH/EPDCCH) for downlink HARQ transmissions within a specific "time-frequency bundling window" linked to an "uplink subframe" for feedback, obtain a Downlink Assignment Index (DL DAI) and determine its mapping value, identify a "second uplink subframe" and an uplink carrier for sending feedback, map HARQ-ACK bits for each feedback unit to a feedback bit sequence using the DL DAI mapping value, and transmit these HARQ-ACK bits on the chosen uplink carrier in the determined second uplink subframe. This uplink carrier includes a "first uplink carrier" for unlicensed bands and a "second uplink carrier" for licensed or unlicensed bands.
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August 4, 2020
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